Publications by authors named "Xiao-Ying Xu"

72 Publications

Welan gum promoted the growth of rice seedlings by enhancing carbon and nitrogen assimilation.

Carbohydr Res 2020 Dec 17;498:108181. Epub 2020 Oct 17.

College of Food Science and Light Industry, Nanjing Tech University, No. 30 Puzhu South Road, Pukou District, Nanjing, 211800, China. Electronic address:

Based on the characteristics of natural polysaccharides in film-forming, chelating, and environmental friendly, a natural polysaccharide fertilizer agent was selected to increase the utilization of nitrogen fertilizer and increase plant growth. Five polysaccharides: xanthan gum, guar gum, fenugreek gum, welan gum and chitosan were screened for plant growth promoting effect. The results showed that welan gum had the most significant effect on promoting the growth of rice seedlings, and the concentrations of 0.1 mg mL and 0.15 mg mL showed the best growth effects. The effects of welan gum on nitrogen utilization in rice seedlings were investigated. Results showed welan gum increased the contents of ammonium, nitrate, free amino acids, and proteins in rice seedlings. There were four key enzymes of nitrogen metabolism which are nitrate reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase significantly enhanced by welan gum though up-regulating the transcriptional levels of these enzymes. Therefore, nitrogen uptake and nitrogen metabolism in rice seedlings were promoted to increase the biomass of rice seedlings. Based on the research, results showed that welan gum could constitute a promising fertilizer in the future.
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http://dx.doi.org/10.1016/j.carres.2020.108181DOI Listing
December 2020

Adverse Factors of Treatment Response and Overall Survival in Pediatric and Adult Patients with Pineoblastoma.

Cancer Manag Res 2020 18;12:7343-7351. Epub 2020 Aug 18.

Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China.

Objective: Intracranial pineoblastomas are rare neoplasms with poor prognosis. The aim of this study was to describe the independent prognostic factors and treatment strategies for overall survival in pediatric and adult patients.

Methods: Sixty-four patients were surgically treated between January 2012 and December 2018.

Results: The series included 37 (57.8%) males and 27 (42.2%) females. Gross total resection was achieved in 41 (64.1%) cases, and the 1-, 3-, and 5-year rates of overall survival were 86.3, 52.3, and 36.6%, respectively. In the pediatric group (n=42), 28 patients (66.7%) were male, with the median, and the mean age was 4 and 6.2±4.7 years, respectively. After a median follow-up of 25.0 months, twenty-six patients (61.9%) died, and the 1-, 3-, and 5-year rates of overall survival were 84.9, 46.4, and 26.7%, respectively. Postoperative radiotherapy (p=0.058) and postoperative chemotherapy (p=0.183) had a positive influence on the increased overall survival. Meanwhile, postoperative radiotherapy combined with chemotherapy following surgery had a positive impact on overall survival (p=0.174, Log rank). In the adult group, the mean overall survival was 67.3±9.3 months (range, 0.8-95.3 months), and the 1-, 3-, and 5-year rates of overall survival were 89.5, 64.4, and 64.4%, respectively. In this group, no statistical association was observed between clinical factors and outcomes. However, patients who received postoperative radiotherapy (60.7 vs 57.6 month, mean survival; p=0.510, Log rank) or chemotherapy (63.0 vs 59.9 month, mean survival; p=0.404, Log rank) had better survival rates compared with those who declined.

Conclusion: In the pediatric group, surgery with postoperative radiotherapy and chemotherapy was a favorable factor for overall survival. In the adult group, a positive trend in overall survival was found when patients received radiation and/or chemotherapy following surgery.
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http://dx.doi.org/10.2147/CMAR.S258476DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7443452PMC
August 2020

Coumarin-3-formylpyrazoles as 3-carbon synthons in cyclocondensation for the synthesis of spiro-fused pentacyclic spirooxindoles.

Org Biomol Chem 2020 02 14;18(5):845-850. Epub 2020 Jan 14.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China. and Institute for Advanced Study, Chengdu University, Chengdu, 610106, China.

Coumarin-3-formylpyrazoles have been synthesized and applied as 3-carbon synthons in reaction with 3-hydroxyoxindoles by using DABCO as the catalyst. A range of structurally diverse spiro-fused pentacyclic spirooxindoles, bearing a spirooxindole-γ-lactone and a 3,4-dihydrocoumarin substructure, could be smoothly obtained in good to excellent yields (up to 99%) with excellent diastereoselectivities (all cases >20 : 1 dr). The asymmetric version of this tandem reaction was preliminarily investigated by using chiral organocatalysts.
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http://dx.doi.org/10.1039/c9ob02434dDOI Listing
February 2020

Organocatalytic Asymmetric Dearomatization of 3-Nitroindoles and 3-Nitrobenzothiophenes via Thiol-Triggered Diastereo- and Enantioselective Double Michael Addition Reaction.

Org Lett 2019 Jul 28;21(14):5452-5456. Epub 2019 Jun 28.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu 610041 , China.

Organocatalytic asymmetric dearomatization of 3-nitroindoles and 3-nitrobenzothiophenes by reaction with ethyl 4-mercapto-2-butenoate has been developed. A range of chiral tetrahydrothiopheneindolines and tetrahydrothiophenebenzothiophenes bearing three contiguous stereocenters are obtained in high yields with good diastereoselectivities and excellent enantioselectivities. This is the first example of thiol-triggered catalytic asymmetric dearomatization of 3-nitroindoles and 3-nitrobenzothiophenes.
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http://dx.doi.org/10.1021/acs.orglett.9b01688DOI Listing
July 2019

Chiral Bifunctional Amine-Squaramide-Catalyzed Highly Diastereo- and Enantioselective Michael/Aldol Cascade Reaction of 2-Mercaptobenzaldehyde and α,β-Unsaturated 7-Azaindoline Amides.

J Org Chem 2019 Jun 30;84(12):7984-7994. Epub 2019 May 30.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu 610041 , China.

A highly diastereo- and enantioselective Michael/aldol cascade reaction of 2-mercaptobenzaldehyde and α,β-unsaturated 7-azaindoline amides has been developed. Using as low as 1 mol % cinchonidine-derived bifunctional squaramide as the catalyst, a range of enantioenriched thiochromenes containing three contiguous stereogenic centers were smoothly obtained in excellent results (all cases >20:1 dr, 88-99% yield and ≥99% ee). The 7-azaindoline moiety of α,β-unsaturated 7-azaindoline amides has been demonstrated to be vital for the high reactivity and excellent stereoselectivity.
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http://dx.doi.org/10.1021/acs.joc.9b00837DOI Listing
June 2019

Phosphine-catalyzed dearomative (3 + 2) annulation of 2-nitrobenzofurans and nitrobenzothiophenes with allenoates.

Org Biomol Chem 2019 05;17(21):5294-5304

Institute for Advanced Study, Chengdu University, Chengdu 610106, China.

An efficient Ph2PMe-catalyzed dearomative (3 + 2) annulation of 2-nitrobenzofurans, 2-nitrobenzothiophenes, and 3-nitrobenzothiophenes with allenoates has been developed. With the developed protocol, a series of structurally important cyclopenta[b]benzofurans and cyclopenta[b]benzothiophenes were obtained in good to excellent yields (up to 98%) under mild conditions. In addition, preparative-scale experiments and transformations were conducted to exemplify the synthetic utility. The asymmetric version of this dearomative (3 + 2) annulation reaction was tentatively investigated by using chiral phosphine catalysts.
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http://dx.doi.org/10.1039/c9ob00775jDOI Listing
May 2019

[Effect of electroacupuncture on neurological deficit and activity of TLR2/NF-κB signaling in ce-rebral ischemia /reperfusion injury rats].

Zhen Ci Yan Jiu 2019 Apr;44(4):242-7

Department of Rehabilitation, Mianyang City Hospital of Traditional Chinese Medicine, Mianyang 621000, Sichuan Province.

Objective: To observe the effect of electroacupuncture (EA) on neurological behavior and activity of Toll-like receptor 2 / nuclear factor kappa B (TLR2/NF-κB) signaling of the ischemic cerebral area in cerebral ischemia-reperfusion injury (CIRI) rats, so as to explore its mechanisms underlying improvement of CIRI.

Methods: A total of 120 male SD rats were randomly divided into blank control, sham operation, model, EA and EA+NF-κB inhibitor (Pyrrolidine Dithiocarbamate Hydrochloride, PDTC, EA+PDTC) groups which were further divided into 3, 7, 14 and 28 d subgroups (=6 in each subgroup). The CIRI model was established by occlusion of the middle cerebral artery for 90 min, followed by reperfusion. EA (1-20 Hz, 6 V) was applied to "Shuigou" (GV26), "Neiguan" (PC6), "Sanyinjiao" (SP6) and "Weizhong" (BL40) for 30 min, once a day for 28 days. For rats of the EA+PDTC group, PDTC solution (120 mg/kg) was intraperitoneally injected on the 3 day after successful modeling and before EA intervention. The neurological deficit severity (Zea Longa score) was assessed 3, 7, 14 and 28 days after modeling. The expression levels of TLR2, Interleukin-1 receptor-associated kinase (IRAK) and NF-κB mRNAs in the ischemic penumbra region of brain tissue were detected by real-time fluorescence quantitative PCR.

Results: Following modeling, the neurological deficit scores were significantly increased from the 3 day on after CIRI (<0.05), the expression levels of TLR2 mRNA on day 3, 7, 14 and 28, and IRAK mRNA on day 3 and 7, as well as NF-κB mRNA on day 3, 7 and 14 were significantly up-regulated in the model group relevant to the blank control group (<0.05). After EA intervention, the neurological deficit scores were significantly decreased in the EA group on day 3, 7 and 28 and in the EA+PDTC group on day 3, 7, 14 and 28 in comparison with those of the model group (<0.05). In addition, the expression levels of TLR2 mRNA and NF-κB mRNA on day 3, 7 and 14 in the EA group, and on day 3, 7, 14 and 28 in the EA+PDTC group, IRAK mRNA on day 3 in the EA and EA+PDTC group were significantly down-regulated (<0.05), but those of IRAK mRNA on day 14 and 28 in the EA group were significantly up-regulated in comparison with those of the model group (<0.05). The effect of the EA+PDTC was obviously superior to that of simple EA in down-regulating the expression of TLR2 (on day 28), and IRAK (on day 3, 14, 28), and NF-κB (on day 3, 7 and 14) (all <0.05).

Conclusion: EA stimulation can improve the symptoms of neurological deficits in CIRI rats, which may be related to its effect in suppressing the expression of TLR2, NF-κB and IRAK mRNAs of the ischemic cerebral tissue, i.e., down-regulating the activity of TLR2/NF-κB signaling.
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http://dx.doi.org/10.13702/j.1000-0607.180553DOI Listing
April 2019

Organocatalyzed Asymmetric Dearomative Aza-Michael/Michael Addition Cascade of 2-Nitrobenzofurans and 2-Nitrobenzothiophenes with 2-Aminochalcones.

J Org Chem 2019 04 25;84(7):4381-4391. Epub 2019 Mar 25.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu 610041 , China.

An organocatalyzed dearomative aza-Michael/Michael addition cascade of 2-nitrobenzofurans and 2-nitrobenzothiophenes with 2-aminochalcones has been developed, opening a new channel to access a series of optically active tetrahydrobenzofuro[3,2- b]quinolines and tetrahydrobenzo[4,5]thieno[3,2- b]quinolines bearing three contiguous stereocenters with excellent diastereo- and enantioselectivities (all cases >20:1 dr, up to 99% ee). This study features the first asymmetric dearomative cascade reaction of 2-nitrobenzofurans and 2-nitrobenzothiophenes beginning with aza-Michael addition. The potential applications of the methodology were demonstrated by the preparative-scale experiment and the versatile transformations of the products.
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http://dx.doi.org/10.1021/acs.joc.9b00401DOI Listing
April 2019

Missense mutation in PRKCQ is associated with Crohn's disease.

J Dig Dis 2019 May 23;20(5):243-247. Epub 2019 Apr 23.

Department of Gastroenterology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Objective: Recent genome-wide association studies have demonstrated that rs2236379 in PRKCQ is a novel significant locus for Crohn's disease (CD). However, the association has not been replicated in any populations. We therefore aimed to investigate the prevalence of the PRKCQ rs2236379 variant in the Chinese Han population and evaluate whether the genetic variant of PRKCQ confers susceptibility to CD and is associated with its clinical characteristics.

Methods: A total of 283 patients with CD and 381 healthy controls were enrolled. Genomic DNA was extracted from their whole blood samples and polymerase chain reaction-restriction fragment length polymorphism was used for genotyping. The association between PRKCQ polymorphisms and susceptibility to CD, and between genotypes and clinical phenotypes was analyzed.

Results: A higher frequency of the T allele was discovered in CD patients than in healthy controls (P = 0.027). A significant difference in the distribution of the TT and CT/CC genotypes was observed between CD patients and controls (P = 0.024). The TT genotype showed a significant association with susceptibility to CD (odds ratio 1.647, 95% confidence interval: 1.088-2.574, P = 0.019). Patients with CD with the rs2236379 TT mutant risk genotype were most likely to exhibit perianal disease (P = 0.044).

Conclusions: Our research revealed an association between the PRKCQ rs2236379 (C>T) and CD. The TT homozygous mutation increased the risk of developing CD and may contribute to perianal disease.
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http://dx.doi.org/10.1111/1751-2980.12717DOI Listing
May 2019

Organocatalyzed Dearomative Cycloaddition of 2-Nitrobenzofurans and Isatin-Derived Morita-Baylis-Hillman Carbonates: Highly Stereoselective Construction of Cyclopenta[ b]benzofuran Scaffolds.

Org Lett 2019 02 14;21(3):660-664. Epub 2019 Jan 14.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu 610041 , China.

The first organocatalyzed asymmetric dearomative cycloaddition between 2-nitrobenzofurans and isatin-derived Morita-Baylis-Hillman carbonates has been developed. Using a modified cinchona alkaloid as the catalyst, a series of structurally diverse cyclopenta[ b]benzofuran derivatives with three contiguous stereocenters, including a spiro-quaternary chiral center, could be smoothly obtained in excellent results (all cases >20:1 dr, up to 99% yield and 98% ee). The utility of this method was showcased by the versatile transformations of the product.
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http://dx.doi.org/10.1021/acs.orglett.8b03786DOI Listing
February 2019

Facile synthesis of fused polycyclic compounds via intramolecular oxidative cyclization/aromatization of β-tetralone or β-tetralone oximes.

Org Biomol Chem 2018 11;16(46):9003-9010

School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000, China.

A mild and efficient NBS promoted intramolecular oxidative cyclization/aromatization of β-tetralone oximes has been explored. Under the optimized conditions, fused α-carbolines containing pentacyclic rings were obtained in moderate to good yields. Furthermore, various benzo[5,6]chromeno[2,3-b]indoles were successfully synthesized in moderate yields from β-tetralones using slightly modified conditions. We proposed a possible reaction pathway based on the experimental results.
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http://dx.doi.org/10.1039/c8ob02031kDOI Listing
November 2018

Synthesis of polycyclic spirooxindoles via an asymmetric catalytic one-pot stepwise Aldol/chloroetherification/aromatization procedure.

Org Biomol Chem 2018 09;16(36):6647-6651

School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000, China.

A general method for the synthesis of chiral pentacyclic spirooxindoles containing a tetrahydropyrano[2,3-b]indole scaffold through a one-pot stepwise sequence from 3-(3-indolomethyl)oxindole, paraformaldehyde and NCS is reported. Furthermore, the pentacyclic spirooxindoles could be transformed to bispirooxindole and other structurally diverse spirocyclic oxindoles.
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http://dx.doi.org/10.1039/c8ob01713aDOI Listing
September 2018

Organocatalytic Asymmetric [3 + 2] Cycloaddition of N-2,2,2-Trifluoroethylisatin Ketimines with β-Trifluoromethyl Electron-Deficient Alkenes: Access to Vicinally Bis(trifluoromethyl)-Substituted 3,2'-Pyrrolidinyl Spirooxindoles.

Org Lett 2018 08 25;20(15):4453-4457. Epub 2018 Jul 25.

Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu , 610041 , China.

N-2,2,2-Trifluoroethylisatin ketimines with β-trifluoromethyl enones, 3-trifluoroethylidene oxindole, and 3-trifluoroethylidene benzofuranone can undergo asymmetric [3 + 2] cycloaddition, catalyzed by chiral bifunctional squaramide-tertiary amine catalysts, affording a wide spectrum of 3,2'-pyrrolidinyl spirooxindoles. The significance of this protocol is highlighted by its extremely high efficiency in the construction of the structurally diverse spirocyclic oxindoles, bearing a vicinally bis(trifluoromethyl)-substituted pyrrolidine moiety, including four contiguous stereocenters, in high yields with excellent stereocontrol.
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http://dx.doi.org/10.1021/acs.orglett.8b01730DOI Listing
August 2018

An organocatalytic asymmetric Mannich reaction of pyrazoleamides with cyclic trifluoromethyl ketimines: enantioselective access to dihydroquinazolinone skeletons.

Org Biomol Chem 2018 05;16(18):3372-3375

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

An organocatalyzed asymmetric Mannich reaction of pyrazoleamides and cyclic trifluoromethyl ketimines with a chiral bifunctional amine-squaramide as the catalyst was developed. A wide range of trifluoromethyl dihydroquinazolinone derivatives bearing adjacent quaternary and tertiary stereogenic centers were readily obtained in good to excellent yields (up to 99%) with high diastereo- and enantioselectivities (up to 99% ee and >20 : 1 dr). The large scale experiment and transformation of the product have also been demonstrated.
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http://dx.doi.org/10.1039/c8ob00707aDOI Listing
May 2018

Organocatalyzed Enantioselective Conjugated Addition of Sodium Bisulfite to β-Trifluoromethyl-α,β-unsaturated Ketones.

J Org Chem 2018 05 30;83(10):5771-5777. Epub 2018 Apr 30.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry , Chinese Academy of Sciences , Chengdu 610041 , China.

An efficient organocatalyzed enantioselective conjugated addition of sodium bisulfite to β-trifluoromethyl-α,β-unsaturated ketones using a cinchona alkaloid-derived squaramide catalyst is presented. A series of optically active sulfonic acids, bearing a tertiary stereocenter connecting a CF group and a SOH group, were obtained in excellent yields with high enantioselectivities (up to 99% yield and 97% ee) under mild conditions. This method will provide an efficient, economic, and green route to access chiral sulfonic acid compounds.
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http://dx.doi.org/10.1021/acs.joc.8b00171DOI Listing
May 2018

An asymmetric organocatalytic vinylogous Mannich reaction of 3-methyl-5-arylfuran-2(3H)-ones with N-(2-pyridinesulfonyl) imines: enantioselective synthesis of δ-amino γ,γ-disubstituted butenolides.

Org Biomol Chem 2018 03;16(10):1636-1640

Institute for Advanced Study, Chengdu University, Chengdu 610106, China.

An asymmetric organocatalytic vinylogous Mannich reaction of 3-methyl-5-arylfuran-2(3H)-ones with N-(2-pyridinesulfonyl)imines has been developed with 5 mol% thiourea-tertiary amine as the catalyst. A series of δ-amino γ,γ-disubstituted butenolides bearing adjacent quaternary and tertiary stereocenters are efficiently obtained with satisfactory results (up to 90% yield, 90 : 10 dr, and 95 : 5 er).
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http://dx.doi.org/10.1039/c7ob03117cDOI Listing
March 2018

Diastereo- and Enantioselective Dearomative [3 + 2] Cycloaddition Reaction of 2-Nitrobenzofurans with 3-Isothiocyanato Oxindoles.

Org Lett 2018 02 31;20(4):909-912. Epub 2018 Jan 31.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences , Chengdu 610041, China.

Enantioselective dearomative [3 + 2] cycloaddition reaction of 2-nitrobenzofurans with 3-isothiocyanato oxindoles was developed. The reaction employs a chiral bis(oxazoline)/Zn(OTf) catalyst, allowing a practical, straightforward access to structurally diverse spirooxindoles containing a 2,3-dihydrobenzofuran motif and three contiguous stereocenters with excellent diastereo- and enantioselectivities. The synthetic potentials of the method have been demonstrated by the scale-up experiment and transformations of the products. The preliminary mechanism was investigated with experimental observations, nonlinear effects studies, and MS experiments.
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http://dx.doi.org/10.1021/acs.orglett.7b03667DOI Listing
February 2018

Multiple Hydrogen-Bonding Bifunctional Thiourea-Catalyzed Asymmetric Dearomative [4 + 2] Annulation of 3-Nitroindoles: Highly Enantioselective Access to Hydrocarbazole Skeletons.

Org Lett 2017 09 15;19(17):4508-4511. Epub 2017 Aug 15.

Institute for Advanced Study, Chengdu University , Chengdu 610106, China.

A method for the enantioselective construction of hydrocarbazole skeletons through dearomative [4 + 2] annulation of 3-nitroindoles with Nazarov reagents is reported. The reactions use multiple hydrogen-bonding bifunctional thiourea as catalyst and are highly diastereo- and enantioselective (up to >20:1 dr and >99% ee). The protocol was demonstrated by preparative-scale experiment and the versatile conversion of the products. The multiple hydrogen-bonding in the catalyst plays a pivotal role in the reactivity and stereoselectivity.
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http://dx.doi.org/10.1021/acs.orglett.7b02068DOI Listing
September 2017

The organocatalytic asymmetric Neber reaction for the enantioselective synthesis of spirooxindole 2H-azirines.

Org Biomol Chem 2016 Nov;14(46):10946-10952

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

The asymmetric Neber reaction of 3-O-sulfonyl ketoxime, in situ generated from isatin ketoxime and sulfonyl chloride, for the synthesis of chiral spirocyclic oxindole compounds is reported. With the developed protocol, a range of chiral spirooxindole 2H-azirines could be obtained in good to excellent yields and up to a 92 : 8 enantiomeric ratio by using (DHQD)PHAL as the catalyst. This methodology is the only example of the catalytic asymmetric construction of spirooxindole 2H-azirine compounds.
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http://dx.doi.org/10.1039/c6ob02220kDOI Listing
November 2016

Organocatalytic asymmetric [3+2] cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with 3-alkenyl-5-arylfuran-2(3H)-ones.

Chem Commun (Camb) 2016 Sep;52(78):11708-11711

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

A highly diastereo- and enantioselective [3+2] cycloaddition reaction of N-2,2,2-trifluoroethylisatin ketimines and 3-alkenyl-5-arylfuran-2(3H)-ones was developed with 1 mol% thiourea-tertiary amine as the catalyst. A series of spiro[pyrrolidin-3,2'-oxindoles] bearing four consecutive stereocenters, including two vicinal spiro-quaternary chiral centers, were efficiently obtained with excellent results (up to >99% yield, >20 : 1 dr, and >99% ee).
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http://dx.doi.org/10.1039/c6cc06367eDOI Listing
September 2016

Michael Addition-Lactonization of Arylacetyl Phosphonate to β,γ-Unsaturated α-Keto Esters for the Synthesis of Chiral syn-3,4-Dihydropyranones and 5,6-Dihydropyranones.

Org Lett 2016 10 21;18(19):5110-5113. Epub 2016 Sep 21.

University of Chinese Academy of Sciences , Beijing 100049, China.

Catalytic asymmetric Michael addition-lactonization of arylacetyl phosphonates to β,γ-unsaturated α-keto esters by a chiral bifunctional thiourea-tertiary amine was established. Using the developed protocol, a range of optically pure syn-3,4-dihydropyranones were generated in good yields with good to excellent stereoselectivities (up to >20:1 dr and 99% ee). Meanwhile, when stoichiometric diisopropylethylamine and 1,8-diazabicyclo[5.4.0]undec-7-ene were used as the base for the same reaction, a series of 5,6-dihydropyranones could be obtained in moderate to good yields (53-75% yield).
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http://dx.doi.org/10.1021/acs.orglett.6b02558DOI Listing
October 2016

Recent (2000-2015) developments in the analysis of minor unknown natural products based on characteristic fragment information using LC-MS.

Mass Spectrom Rev 2018 03 24;37(2):202-216. Epub 2016 Jun 24.

Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.

Liquid chromatography-Mass Spectrometry (LC-MS) has been widely used in natural product analysis. Global detection and identification of nontargeted components are desirable in natural product research, for example, in quality control of Chinese herbal medicine. Nontargeted components analysis continues to expand to exciting life science application domains such as metabonomics. With this background, the present review summarizes recent developments in the analysis of minor unknown natural products using LC-MS and mainly focuses on the determination of the molecular formulae, selection of precursor ions, and characteristic fragmentation patterns of the known compounds. This review consists of three parts. Firstly, the methods used to determine unique molecular formula of unknown compounds such as accurate mass measurements, MS spectra, or relative isotopic abundance information, are introduced. Secondly, the methods improving signal-to-noise ratio of MS/MS spectra by manual-MS/MS or workflow targeting-only signals were elucidated; pure precursor ions can be selected by changing the precursor ion isolated window. Lastly, characteristic fragmentation patterns such as Retro-Diels-Alder (RDA), McLafferty rearrangements, "internal residue loss," and so on, occurring in the molecular ions of natural products are summarized. Classical application of characteristic fragmentation patterns in identifying unknown compounds in extracts and relevant fragmentation mechanisms are presented (RDA reactions occurring readily in the molecular ions of flavanones or isoflavanones, McLafferty-type fragmentation reactions of some natural products such as epipolythiodioxopiperazines; fragmentation by "internal residue loss" possibly involving ion-neutral complex intermediates). © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:202-216, 2018.
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http://dx.doi.org/10.1002/mas.21514DOI Listing
March 2018

Enantioselective synthesis of chiral α,β-unsaturated γ-substituted butyrolactams by organocatalyzed direct asymmetric vinylogous Michael addition of α,β-unsaturated γ-butyrolactam to 2-enoylpyridines.

Org Biomol Chem 2016 Jul;14(27):6568-76

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

An organocatalyzed direct asymmetric vinylogous Michael addition reaction of α,β-unsaturated γ-butyrolactam to 2-enoylpyridines has been developed with a chiral bifunctional amine-squaramide as the catalyst. This approach provides easy access to a series of optically active α,β-unsaturated γ-substituted butyrolactams in high yields (up to 99%) with excellent diastereoselectivities (up to >99 : 1) and enantioselectivities (up to >99% ee).
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http://dx.doi.org/10.1039/c6ob01191hDOI Listing
July 2016

Organocatalytic Asymmetric Michael Addition of 3-Pyrrolyloxindoles to β-Phthalimidonitroethene for the Synthesis of 3,3'-Disubstituted Oxindoles Bearing Contiguous 3,α,β-Triamino Functionality.

J Org Chem 2016 07 17;81(13):5759-65. Epub 2016 Jun 17.

University of Chinese Academy of Sciences , Beijing 100049, China.

An organocatalytic asymmetric Michael addition reaction of 3-pyrrolyloxindoles to β-phthalimidonitroethene has been developed with a bifunctional thiourea-tertiary amine as the catalyst. A range of 3,3'-disubstituted oxindoles bearing contiguous 3,α,β-triamino functionality could be obtained in high yields with good diastereoselectivities and high enantioselectivities (up to 99% yield, 99:1 dr, and 98% ee). The higher reactivity of β-phthalimidonitroethene compared to the reactivity of ordinary nitroalkenes in the reaction with 3-pyrrolyloxindoles was demonstrated by contrast experiments.
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http://dx.doi.org/10.1021/acs.joc.6b00896DOI Listing
July 2016

Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors.

Beilstein J Org Chem 2016 16;12:295-300. Epub 2016 Feb 16.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee).
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http://dx.doi.org/10.3762/bjoc.12.31DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4778496PMC
March 2016

A Neber approach for the synthesis of spiro-fused 2H-azirine-pyrazolone.

Org Biomol Chem 2016 Feb;14(6):1946-9

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

A base-mediated Neber reaction of enaminopyrazolones, which are the tautomers of 4-acyloxime-2-pyrazolin-5-ones, with sulfonyl chlorides was achieved. With this developed approach, a range of spiro-fused 2H-azirine-pyrazolones were obtained in good yields under mild conditions. A preliminary trial of a catalytic asymmetric version of the Neber reaction was conducted and gave promising enantioselectivity.
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http://dx.doi.org/10.1039/c5ob02559aDOI Listing
February 2016

An unprecedented protocol for the synthesis of 3-hydroxy-3-phenacyloxindole derivatives with indolin-2-ones and α-substituted ketones.

Org Biomol Chem 2016 Jan 16;14(4):1395-401. Epub 2015 Dec 16.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

An unprecedented reaction between indolin-2-ones and α-substituted ketones has been developed. Using this protocol, a wide range of biologically important 3-hydroxy-3-phenacyloxindole derivatives could be obtained in good yield (up to 93%) under mild reaction conditions. A possible mechanism of this reaction was tentatively proposed based on some control experiments and MS spectrometry analysis.
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http://dx.doi.org/10.1039/c5ob02391bDOI Listing
January 2016

An unprecedented protocol for the synthesis of 3-hydroxy-3-phenacyloxindole derivatives with indolin-2-ones and α-substituted ketones.

Org Biomol Chem 2016 Jan 16;14(4):1395-401. Epub 2015 Dec 16.

National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.

An unprecedented reaction between indolin-2-ones and α-substituted ketones has been developed. Using this protocol, a wide range of biologically important 3-hydroxy-3-phenacyloxindole derivatives could be obtained in good yield (up to 93%) under mild reaction conditions. A possible mechanism of this reaction was tentatively proposed based on some control experiments and MS spectrometry analysis.
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http://dx.doi.org/10.1039/c5ob02391bDOI Listing
January 2016

Freeze-thaw Caenorhabditis elegans freeze-thaw stress response is regulated by the insulin/IGF-1 receptor daf-2.

BMC Genet 2015 Dec 3;16:139. Epub 2015 Dec 3.

The Department of Geriatrics, Ren-Ji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.

Background: Adaption to cold temperatures, especially those below freezing, is essential for animal survival in cold environments. Freezing is also used for many medical, scientific, and industrial purposes. Natural freezing survival in animals has been extensively studied. However, the underlying mechanisms remain unclear. Previous studies demonstrated that animals survive in extremely cold weather by avoiding freezing or controlling the rate of ice-crystal formation in their bodies, which indicates that freezing survival is a passive thermodynamic process.

Results: Here, we showed that genetic programming actively promotes freezing survival in Caenorhabditis elegans. We found that daf-2, an insulin/IGF-1 receptor homologue, and loss-of-function enhanced survival during freeze-thaw stress, which required the transcription factor daf-16/FOXO and age-independent target genes. In particular, the freeze-thaw resistance of daf-2(rf) is highly allele-specific and has no correlation with lifespan, dauer formation, or hypoxia stress resistance.

Conclusions: Our results reveal a new function for daf-2 signaling, and, most importantly, demonstrate that genetic programming contributes to freezing survival.
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http://dx.doi.org/10.1186/s12863-015-0298-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4669615PMC
December 2015
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